Immunoglobulin A is the most abundant of the five classes of immunoglobulin and is primarily found in the mucosa of the gastrointestinal tract and the respiratory tract. There are two types of immunoglobulin A, secretory IgA and serum IgA. Serum IgA is generally a monomer found in the serum of many species, where it functions as a second line of defense which mediates the elimination of pathogens that have breached the mucosal surface. Secretory IgA (SIgA) is dimeric or polymeric and contains a secretory component in addition to IgA. SIgA is a common constituent of breast milk for the young and a secreted protein into the gastrointestinal system during post-weaned development and adulthood. It has been suggested that systemic administration of IgA may be protective against the progression of inflammation that leads to septic shock. Currently there is no method devised to correct a deficiency of SIgA in the gastrointestinal tract of animals and humans and no evidence that said administration can correct these disorders.
SIgA has been shown to bind a wide variety of environmental proteins and polysaccharides (e.g., bacteria, viruses, toxins, food components) preventing their entry into the body and the activation of host inflammatory immune mechanisms. Currently, there is no mechanism known for the production of SIgA with a diverse range of antigen binding activity apart from synthesis in an animal (e.g., SIgA with diverse antigen binding activity cannot be produced using chemistry, recombinant microorganism in fermentation or stem cells). Further, the more diverse the exposure of an animal to environmental insult the greater the repertoire and diversity of SIgA activity. To explore the use of SIgA as a dietary/oral supplement for the treatment of disease, there must be a source of SIgA that can be directly collected from an animal. In addition, it is advantageous that the amount of material collected is cost effective relative to the treatment of the disease malady because many diseases treatable with SIgA are not life threatening enough to warrant costly pharmaceutical therapy.
What is needed is a source of SIgA that can be used as a supplement to treat SIgA related disorders.